Abstracts Book - IMRC 2018

• SF2-P022
EFFECT OF COMPLEXING AGENTS ON OPTIMIZED DEPOSITION OF
CDS BUFFER LAYER FOR HIGH-EFFICIENT CIGSE SOLAR CELLS
Onyekachi Nwakanma 1 , Jorge Narro Rios 1 , Velumani Subramaniam 1
1 Centro de Investigación y de Estudios Avanzados del IPN - CINVESTAV, Departamento de
Ingeniería Eléctrica, Mexico.
Several studies are being carried out to improve and optimize the properties of
the different layers of the solar cells to obtain higher efficiencies as predicted
theoretically. Cadmium sulphide (CdS) films commonly deposited by chemical
bath method has been successfully employed for preparing the buffer layer of
some high efficient solar cells, including the CdTe and Cu(In,Ga)Se 2 solar cells.
However, the deposition parameters (bath temperature, pH and
concentrations) as well as choice of complexing agents continue to affect the
properties of the deposited films. We studied the chemical bath deposition of
CdS using two different complexing agents (ammonia and acetylacetone) to
observe the effects of the deposition conditions; temperature, pH and the
concentrations of the reactants. The optimized conditions were aimed at
obtaining better growth rate, more carrier charge concentrations on the films,
reduction of homogenous reactions in the solution for deposition (by using
different concentrations of the complexing agents) and a desirable crystal
structure for the deposited thin films. Deposited films were characterized by x-
ray diffraction, scanning electron microscopy and Raman spectroscopy with the
electronic properties of the semiconducting layer characterized by Hall
measurements. X-ray diffractogram showed (002) peaks for the films deposited
and (110) peaks depending on the choice and ratio of complexing agents used.
The bandgap values of the films varied 2.37eV to 2.45eV. Further studies will be
aimed at optimizing the interface properties of the CdS layer and the CIGSe
absorber layer.
Acknowledgment:
We wish to acknowledge the financial support the El Centro Mexicano de
Innovación en Energía Solar (CeMIE Sol) project CeMIESol P-55.
Keywords: CdS, CBD, buffer layer
Presenting authors email: kachinwakanma@yahoo.com